In recent years, as driving support equipment for vehicles, various technologies have been developed and put to practical use. They include placing cameras, etc. in vehicles, for detecting the forward travel environments, and controlling alarms regarding frontward obstacles. They also include technologies for detecting preceding vehicles in the travel environment and controlling the following or alarms regarding such preceding vehicles.
Additionally, technologies have recently been developed for estimating the driver's attention, and varying alarms based on such attention.
For example, Japanese Patent Publication No. Hei 11-276461A1 discloses a technology wherein the driver's eyeball transfer movements are detected, the driver's attention level is estimated from such eyeball transfer movements, and then information is presented earlier when such attention levels are lower.
When a preceding vehicle exists at the front, a necessity arises for the driver to provide enough attention within his forward sight to this preceding vehicle.
However, according to the driver's condition, such attention may be aimless. In the reverse, there may be cases where he invests too much in the attention on the preceding vehicle and be negligent regarding other surrounding information.
The above-mentioned prior art has difficulty distinguishing such changes in the attention relating to preceding vehicles. Technologies for adequately providing alarms to the driver when such preceding vehicles exist, are highly desired.